Randall’s sheath snaps

[double gun]

Does anyone know what rivet or fastener they use on the post side of the snap? If you look inside the sheath, it doesn’t look like they covered the post/rivet base with leather, you can still see the punched hole. There is no rivet base at all visible, so the rivet they use must be pulled into the leather somewhat. Anybody know what they use or how? Is it just a short piece of tube with a flare on both ends?

My apologies for my terminology (or lack of), I don’t work with leather much.
thanks in advance